Sarah Palin is back in the news, with a nationwide bus tour and the planned release of a flattering documentary that reportedly chonicles her career as a feisty and effective "crusader" for the middle class. It's scheduled to be released in media markets in key primary states like Iowa, New Hampshire and Florida, just as her bus rolls by historic landmarks like Lexington and Concord, where Palin will briefly disembark to hold forth on America's past and future "glory".

In fact, Palin probably has something far more foundational in mind: rebuilding her tarnished "brand" as one of the most admired women in America; and among Republicans, regaining the political standing she lost after last November's midterms, when top party officials accused her of sabotaging the GOP's chances of regaining the Senate, with her ill-advised support for extremist Sharron Angle in Nevada and Christine ("I'm Not a Witch") O'Donnell in Delaware.

By any objective reckoning, Palin didn't actually kill the GOP's chances in the Senate, though her support for the wacky neophyte O'Donnell – when an establishment GOP candidate was a virtual shoo-in to win – was clearly ill-advised. In fact, three quarters of the more than 40 Republican candidates Palin supported through her multimillion-dollar fundraising arm, SarahPAC, triumphed – an extraordinary 75% "win" rate. And many top Republicans, not just Palin, supported Angle, who was well on her way to victory until she committed a series of last-minute gaffes, none of them attributable to Palin.

But for those like Bush presidential mastermind Karl Rove, who's made no secret of his desire to drive Palin out of the 2012 race, in favour of his own preferred candidate, any Palin misstep – including the release of her "blood libel" video defending herself against critics who say her attack ads helped Representative Gabrielle Giffords get shot last spring – can prove costly. Her favourability ratings, already at an all-time low among the general public, have steadily slipped among Republicans since the beginning of this year.

But, for all the current media frenzy, there's little real sign that Palin actually plans a bid for the GOP nomination. So far, she's done none of the prep work typically associated with launching a national campaign, including contacting key donors, enlisting strategic consultants, or hiring polling firms to conduct focus groups and other political research. Even rival candidates, whose own prospects could be altered dramatically by a Palin candidacy, say they doubt that the former Alaska governor intends to run.

But as she demonstrated during last year's midterm races, Palin doesn't need to be a presidential candidate to become a major force to be reckoned with. While her support for Tea Party candidates, especially prominent "Mama Grizzlies" like South Carolina's Nikky Haley and New Mexico's Susan Martinez, is well known, Palin has shown a remarkable ability to pivot and support more establishment heavyweights when it suits her fancy. Despite her public image as a "rogue" conservative, in fact, she's clearly tried to position herself as a party power-broker – someone who can "anoint" individual candidates, build bridges between warring and disaffected party constituencies, and perhaps, should the need arise, help ensure the victory of one presidential candidate over another.

Palin's closest relationship, of course, is still with John McCain, who's been surprisingly protective of her in public, given his apparent distaste – expressed privately, and ostensibly off the record – for the way she conducted herself as his vice-presidential running mate. McCain, though, faced a huge political scare last summer when Tea Party firebrand JD Hayworth challenged him for the GOP nomination, and appeared to be gaining in the polls. That is, until Palin came to the rescue with a series of high-profile visits to Arizona that all but demolished Hayworth's credibility as a viable alternative.

And it's not just McCain who owes her, but Texas Governor Rick Perry, who faced a stiff primary challenge from Senator Kay Bailey Hutchison with support from the Bush family dynasty, until Palin saddled up and joined Perry's posse. Palin drew one of the largest crowds in the state's political history when she and her youngest daughter Piper appeared on a stage with Perry, calling him "my friend", and rebutting Tea Party critics who'd accused Perry of wanting Texas to "secede". "He's succeeding, not seceding," Palin declared, citing his record creating jobs, attacking "big government" and backing anti-abortion legislation as proof that Perry was "true blue".

If there's any doubt that a long list of GOP incumbents owe a debt to Palin and are prepared to support her, consider McCain's recent statement – remarkable on its face – that he thinks Palin could "beat Obama", if she were to run. (Although, like most others, he qualified this by saying that she probably wouldn't join the race.) Expect much the same adulation from Representative Michele Bachmann, who's about to announce her own bid for the presidency. Though some are suggesting that the two may become bitter rivals, it's far more likely that Palin is preparing to position herself between Bachmann and other prospective GOP candidates, including Jon Huntsman, who is McCain's chosen political heir, or even Perry, who some see as a second GOP "dark horse" should Huntsman fail to gain traction.

Bachmnan, at 57, is a decade older than Palin, and most people agree she's far more grounded in policy, nimbler on her feet, and on balance, a more consistently, compelling speaker. Palin could easily bide her time and – with all the political "chits" she's earned, and will continue to accumulate, for supporting winning GOP candidates – could well end up with a top post in any new GOP administration. "President Palin" may be unthinkable, at least in 2012, but "Secretary of Energy Palin"? For a party badly in need of attractive Tea Party-friendly politicians who can be promoted to top positions, a plum cabinet appointment could be just what she needs to gain the credibility needed to launch a more serious presidential bid down the road – that is, if she doesn't decide to run in 2016, assuming Obama will have been re-elected in 2012.

Palin says she hopes her bus tour will give the country a powerful history lesson. But with her resurgence, and Madonna-like ability to reinvent herself, she just may give us a history lesson we least expect.